And william e



W. FERRIS AND W. E. MAGIE. HYDRAULIC TRANSMISSION DEvIcE.

APPLICATION FILED FEB. 26.l i916.

W. FERRIS AND W.; E. MAGIE.

HYDRAULIC TRANSMISSION DEVICE.

` APPLICATION man FEB. 2s. 1915.

Patented J illy 8, 1919.

w. mams AND w. E. MAGIE.

HYDRAULIC TRANSMISSION DEVICE.

APPLICATION msu FEB. 2s, Isls.

1,308,844. I A I PatentedJu1y8,1919.

4 SHEETSSHEET 3.

I I I I l w. Finals AND w. "E. MAGIE. HYDRAULIC TRANSMISSION DEVICE.

APPLICATION FILED FEB. 26. |916.

D? m m 8 SMU 0, 1. MVM

STATES PATENT oFFIoE.

FEBBIS, E MILWAUKEE-WISCONSIN, AND WILLIAM E. MAGIE, 0F n EVANSVILLE,INDIANA. 'I

I HYDBAUIIZIC TRANSMISSION DEVICE.

Specification of Lettersv Patent.

' Applicatioii led February 26, 1916. `Serial No. 80,580.

To all whom t may'concer'n.' a

Be it known that we, WALTER FERRIS and i lWILLIAM E. MAGIE, citizens ofthe United States, residing, respectively, at Milwaukee, Wisconsin, andEvansville, Indiana, have 1nvented certain new and useful Improveing, to'improvements in ments in Hydraulic Transmission Devices,

a specification. generally speakydrauhc transaxial type wherein Ourinvention. relates,

missions of the so-called the motor and pump cylinders and istons p areall arranged ingroups axially a out a reservoir or make-up chamber.

central shaft.

In our preferred and pump together with the operating mechanism are all`contained wlthin a single housing. This housing `forms what we preferto call an operating chamber. Within it is: a pressure chambercomprising the the oil orliquid under pressure within the pump and motorcylinders, valve plates, ports and passages. A portion of the housingisgiven over to a This chamlrber is adapted to contain a certain amountof Vmotive fluid in a condition of rest and means are provided forforcing this iiuid from the make-up chamber back into the' operatingchamber either by the pump or hydrostatic pressure or otherwise. A pressure' reliefl is provided for the operating chamber and the operatingchamber is 1ntended to be at all times completely filled with the motivefluid at acertain predetermined pressure." Any introduction of morefluid-will only result in'increased pressure and a. controlled dischargefrom the operatl 4 ing chamber to the reservoir. Since the opmotivefluid, oil leakage from the main pump erating chamber is allthe timefull of the into'4 the operating chamber immedlately l 410a-mnd' thissupply wiu ke@ 5o forces an equal exhaust port, `illn eating therewith.'

quantity of oil back into the the cylinders communin our preferred-formwe `provide a circulating pump which will con-- stantly force a smallsupply of motive fluid from the reservoir into the worklng chamuptherpressure to the desired point and eep the .working chamber -alwaysfilled. To permit this pump always to' operate there must be arelief-valve and this relief valve-is set to keep Aa certainpredetermined pressure in the. valve chamber. j

form-of device the motor Patented July s, 1919.

Our invention is illustrated more or less diagrammatically in the'accompanying drawings, wherein Figure 1 is a longitudinal sectionthrough the housing and parts contained therein with parts omitted;

Fig. 2 is a detail section on an enlarged scale showing part of thedriving and swash plate connections; y

Fig. 3 is a 'section on the line 3 3 of Fig. 2;

4 is a section on thel line 4-4 of Fig. 2; Fig. 5 is an enlargeddetailed the circulating pump;

Fig. 6 is a section on the line 6-6 of section of Fi 1' l Fig.7 is apart elevation and part section along a plane perpendicular to the'planeof the section of 'Fig. 1; and

Fig. 8 is a section of the cylinder ports where they engage the valveplate.

Like parts are indicated 'by like letters throughout the severalfigures'.

Housing.

The cylinder `housing in which'y all the working parts are contained ismade' up 'the v-alve housing but closed at the other end except forcentral axial apertures A8, A. Curved annular walls A, Apinthe ends ofthe housings A1, A2 -form reservoirs or `ma'ke'up chambers A", A8. Thesereservoirs or make-up' chambers may be regarded as one because they areconnected by a pipe A", a portion'of which is coiled as at A to providea cooling or radiating surface whereby the temperature of the oil .may

dangerpoint. A

In the wall of the housing A1 is a screw threaded adjustable plug B.This plug is in line with an aperture B1 in the wall A? and slidablymounted within this aperture is a. pressure relief valve B2. Thispressure relief valve is adapted to be yieldingly seated against thewallv A5 by the spring B3, the

v100 be kept down below a certain predetermined up4 of a plug 1n whichare cut a series of* slots B4 increasing in Width inwardly so that asthe pressure in the main Working chamber increases pressing back the4valve against thespring any fluid in the housing Will be free to passout through these slots.

, The greater the pressure and the further l the aperture ably connectedfor driving with any desired theC plug is moved the greater theeii'ective opening through which such fluid or liquid may pass.

Formed 1n the vvall A6 is a circulating pump housing C. This pump is asingle acting pump havin a piston C1 drivenl by a connecting rod 2reciprocating in a -cylinder C5 located in the housing C. C4 is a springseated intake valve, C a springy seated exhaust valve so that as thepump reciprocatesthe oil is drawn from the reser- Voir As through theintakev valve C4 into the cylinder C5 and thence expelled through theexhaust valve C5 to the interior ofthe Working housing. i

The housings A1., A2 are lbolted to the housing A by means of the capscrews A11 as indicated. The flanges between these two housings areprotected againstJ leakage by the annular rings A12 yand bleeder tubesleading therefrom through pipes A12 communie-ating With the ipe A5, thusrelieving the outer portion of t e packing surface between'these flangesfrom the direct pressure of the -oil in the Working chamber.

y Operating' skafts ami supports. D is a pump shaft projecting outthrough 4 in the housing A2 vand suitprime mover not here shown. D1 is apackving; D2 al, packing ring and D5 a holding- (Tap-l 'the4motor outthrough the' aperture A5 and D4 1s a motor shaft leading from adapted todeliver its power in .any suitable manner. It also is packedas indicatedat theother end of the machine. The shafts D and D4 are each guided andsupported adjacent the ends of the housing by the floating bearings D5.These bearings have spherical ends D6 engaging the spherical surface D7on the housing so that they will be free to move 4and adjust themselvesfor any bending or change in position of the shafts and preventdistortion of the partsl and any binding -or frictional losses. D8 is acentrally disposed hub furnishing separate bearing `surfaces Afor eachof the shafts D, D4. Contained Within the center of this hubis a plug E.This plug E is longitudinally apertured and has at either end the pipesE1,

E2 projecting into the ends of the shafts D D4 respectively. Theseshafts contain oil passages Es leading longitudinally from the ends ofthev pipes E1, E2 to transverse pipes E4. These transverse pipes E4 com-Within Vthe blocks D5 behind the slidable collar or plunger E5. Theslidable collar E5 is in engagement with a shoulder E7 011 the.

shaft so that any oil forced in through the kbearing block in the otherdirection toward the spherical bearing surface. lAn eccentric lpipes E3and E4 to the annular chamberl E5 is provided on the shaft D to driveby.

means of an eccentric collar E9 the connectf ing rod C2 to operate thecirculatlng pump.

The bearing on the shaft in the bearing block is lubricated by the QHflow from this same tube and annular chamberl and a bleeder .pipe E1oleads from the bearing to perm-it run-off of excess oil and to preventthe full oil pressure from coming upon the acking sleeve at the end ofthe shaft. f here is also a bleeder pipe E11 as indicated to permit outflow of oil from the space betv veen the bearingblock and the housing tothe reservoir.

Valve plate and cylinder bmw-el assembly.

F is a valve disk or plate. It 'is as shown centrally located in andintegral with the member A and carries the hu-b D5. This valve plate hasthrough it tWo (crescent shaped ports F1, F2. These ports may each of`them be either an intake or an exhaust port depending on the directionin which the machine is running. When one is an intake' the other isalways an exhaust port. F5, F4 are relief passages leading from theports F1, F2 respectively. 'These passages are controlled each by asafety valve F5 pressed upon a seatF6 by the spring F7 the tension inwhich may be adjusted'by manipulation of the screw-threaded cap F5. Whenthe pressure is suliiciently great to raise this valve the liquidescapes into the valve chamber F" thence through the bleeder pipes F15to the interior of the housing.' F11, F12 are housing so that 4-vvhenthe pressure in one por-brises above the safety point and the reliefvalve is unseated the oil thus forced into `the housing willraisethepressure there and cause oil'to be forced from the housing through thereturn valve into thel opposed' `port, thuskeeping the pressure chamberal- Wa s completely filled.

is a pump barrel, G1 a vmotor barrel. Y

These barrels are, generally speaking, similar one to the other. Theyare mounted for krotation each u on one-arm of the hub D13A andgu-idedan supported thereon. Each inder.

' than they are in' a radial direction because this best utilizes theavailable space and because the area of contact between the barrel andvalve plate is thus reduced to a minimum: They discharge each againstthe valve plate F and are of substantially the same width measured alonga radial line as the ports F1, F2. These ports are controlled by, and'discharged through, the valve plate F. In each cyllnder is a iston Grfree to move back and forth therein. These pistons contain each aspherical bearing G in which sets a ball G8 on the end of a' connectingrod G2. The ball Ais held against the bearing by a disk G1 having aspherical, bearing thereupon. This disk is held in position by afollower nut G11 so as to hold the connecting rod firmly in position inproper relation tothe piston. The center of the piston is apertured asat G12 in registerJ with an oil duct G13 through the connecting rod. G14is a coil spring anchored at one end in the piston G and at the otherend in the follower'nut'Gr11 so that as wear takes place on thesp'herical bearing the spring tends to rotate the follower; nut to tihten 1t on the ball.

4neled driving block ring H H is an annular ring ormed on the wall i 35"A inclined tothe axis of rotation of the shaft, its center being solocated as to bring Y its axis to an intersection with the shaft axisinthe plane of the connecting rod sockets.

On it rests a flanged guide sleeve H1, the.y

flange H2 thereof containing the ball race H15 H1 areballs travelin alonthe ball race and supporting a mova le ba l race H5. This ball race I-Iicarriesvan annular chanided on sleeve H1 and contalmng spaced t ereaboutseven These drivin blocks s to en- H" on the ends of the connecting rodsG. These balls are held firmly seated on the spherical bearings b thefollower rings H1 which are slidab e toward and from the bottom of theblock.

lI is an annular spring late having Iseven apertures therethrou h w ichapertures are in'engagement-with t e projecting fianges I1 on thefollower rings. This s ring plate holds eachI and every one of thefollower 'rings bound in position to clamp. the ball -ends of theconnectin rods close 'in their sockets.- This plate is eld in positionby a lurality of cap screws I2 which pass through 1t and engage the ringH at p omts removed from the follower rings so t Vring'` is notsupported/at those points and thus transmitting yieldin'gly at thespring presses down pipe J 9 this pressure to the follower rings-to hold.them in position and thus by the yielding pressure of this plate eachfollower ring is caused to automatically follow up and compensate forany wear in the ball end. I3 is a s Ppi-ing ring mounted on each of thesleeves 1 and J and held rigidly thereon by the cap screws I". Thisspring ring overlies the channel ring .H0 and presses yieldingly againstitr and holds that ring yieldingly but 'firmly against the ball bearing.The above description applies to both the um and the motor ends of theapparatus, ut t e pump 'end is exactly the same except that the swashplate assembly consisting of the ball bearing, the annular ring and the4blocks which drive the`connecting rods, are

mounted forrotation about an axis at right angles to the shaft, so as topermit adjustment of the stroke of the pump. No such adjustment of themotor is usua l needed, andso the motor parts are shown lixed inposition.

'In the pump assembly then the bearing sleeve or quill J is substltutedfor the bearing sleeve H1. This quill J is mounted on the yoke J2, whichyoke is provided with a pin J2 pivoted `in a bearing plug" J 1 at oneside of the housing A2, and provlded with a control shaft J plvoted at'a plugJ at the other side of thel ring, and J s a packing sleeve toprevent leakage of the oil along the shaft, the bleeder discharging froma point inside the packing ring into the reservoir A, so that thepressure on the packing sleeve is only the pressure in the reservoir,the bearing J1 being thus lubricated by the roil escaping from theworking chamber. The shaft 5 is square as at J 11 so that it maybemanipulated by any suitable wrench, handle .or the like to adjust theinclination of the swash plate and thus the stroke of the pump. J 12 isa filler plug discharging into the reservoir As, whereby the supply ofoil may be replenished. It will be noted that the axis of the shaft J '1and pin J 8 intersects the pump shaft at the same point that the' planelocated by the centers ofthe outer end balls lof the connecting rods,when'the swash plate occupies a neutral position, intersect this shaft,so that no matter what the inclination of the yoke, the movement of theswash plate, whose plane is the plane above referred to, is symmetricalwith respect tothe .pump shaft.'

The parts housing. J7 is a packing interposed between 4the bearingsleeve J andl the pistons Go are, of course, lexactly the same as theparts interposed bewith the cylinder barrels, and since these barrelsare mounted on the shafts as shown, a' connection between the shafts andthe swash plates is necessary. In the case of the pump, the angle of theswash plate is variable, and this connection must, therefore, be bymeans' of some type of universal joint and this universal jointconnection takes care of this inclination and permits a continuousdrive. It is also important that the angular rotative position of theswash plate with respect to the shafts be fixed or constant, and sincethe ordinary or universal joint does not get this desired result, it isnecessary to employ a special type of universal joint which will drivethe driven part so that its angular position will always be the samewith respect to the angular position of the driving f Y has on eitherVside midway the trunnion part, 4.that is to say, a universal joint whichhas what is called a constant velocity ratio.

K is a hub keyed vto the shaft. It carries a spider K1L having a angeK2. On this flange is pivoted a warped ring K3. This ring is trunnionedat c k on two diametrically opposed sides on the flange K2, and

points, a pivoted 'bearing K4,- to which is joined by means ofthe screwK5 a pivoted i bearing K6 on a somewhat similar ring K7.

This ring is slightly smaller in diameter than the ring K3, and ispivoted on opposed sides halfway between the pivoted bearing Kon pinsKS, which project from the ring spider4 K1, is located partially withinthe cylinder barrel. This hub is, of course, keyed to the shaft, and hasresting against it an annular washer L surrounding the shaft. Thiswasher has a spherical surface L1 in engagement with a spherical surfaceL2 on a compensating washer L3, which is supported by the cylinderbarrel. Thus the thrust of the shaft operates to hold the cylinderbarrel firmly and snugly against the valve plate, independent of. anydistortion or displacement of the shafts. The barrels themselves aredriven in unison with the driver by pins L1 projectingl therefrom inengagement with the yokes L5 on the driver.

Resum.

The pressure chamber, as above pointed out, comprises the spaces betweenthe pistons and the valve faces on the pressure side in pump cylindersand motor cylinders; the volume of the main ports in the valve plate,the auxiliary ports to the double check valves, the passages E3inshafts, and the pressure chambers backl of the plungers 'E6 on saidshafts. All of the leakage from this pressure system goes eitherdirectly into the operating chamber past the pistons and valve faces oris returned thereto after leaking from the pressure chamber, along theducts `or between the bearings or past the collars or plungers E6, asthe case maybe.

The operating chamber or inner casing is the space containing thecylinders, valve plate, universal joints and thrust bearings,y

cludes return ducts which receive the leakage around the shaft frompressure chambers back of plungers E6 and return it to the mainoperating chamber, thus relieving the circulating ump from the work ofreturning this leakage from the reservoir system. The piston andcylinders are of` uniform size and stroke, and the ports ofthe valveplate of equal size, and opposite each other. They are so placed asto-insure the division of the'operating chamber into zones of high andlow pressure of equal size. This is the case since the valve ports aredisposed at equalI distances on either side of a line through the centerof the valve plate, and at right angles to the axis of rotation of thepiston controlling ring. The reservoir or make-up chamber is in thiscase dividedv intotwo .sections A7 AB, one at each end of the machme,and connected by an `exterior pipe. The reservoir is characterized bythe fact that it is normally partly full of oil,

the remainder being filled with gaseous material, capable ofaccommodating oil eX- pansion, the pressure being lower than -in theoperating chamber. The pressure in the reservoir may be substantiallythe same as that in the operating chamber if the machine is builtwithout a circulating pump; or the operating chamber pressure maybeconsiderably higher than the reservoirpressure, this increase'beingincidental to the operation of j the circulating pump. The reservoirsystem also comprises the leakage return ducts near the ends of the mainshafts, the end of the operating shaft, from the flanged joints, and thereturn pipe from the auxiliary or 1 relief valve reservoir to main orpump reservoir. Duets receive the leakage :fromv the leakage isautomatically returned from the lowest pressure zone into the nextpressure operating chamber system along the main shaft and operatingshaft, and return it directly to the main reservoir,thus relieving theshaft packings from the work of holding back the pressure of theoperating chamber. The shaft packings are therefore only subjected toreservoir pressure, which `in most t cases will f approximate atmospherepressure, or may be lower.

From the above it appears that thev entire casing is divided into threezones of pressure. passing automatically into the next lower zone.l vThepackings around the external shaft openings only ha\'e to hold thepressure of the lowestl or reservoir zone. The

zone or operating chamber by the expansive pressure of thet gas or airwhich occupies part of the reservoir system or by the circu-v lating umpwhen the circulating pump lis used. his circulating pump will also serveto augment the pressure in the operating.

chamber when so desired. Certain advantages in thefoperation of themachine can be attained by a gradual circulation of the oil from thereservoir into the operating chainber and back again. These advantageslie principally in giving each fraction of the oil in turn anopportunity to leavethe operating chamber, where it is violentlyagitated, n

and spend some time in the reservoir-,where it is practically at restandhas a chance to deposit any solid matter held in suspension,

y and to free itself from `entrained air. This circulation ismaintained'by means of the j plunger pumpfof small capacity andin thistrans casel operated by the eccentric formed on the main pump shaft. Ateach stroke this pump voir to operating chamber throu h the check valvesand an equal uantity is orced out of y v the operating'cham r throughthe relief 1valve,- returning to the main reservoir through theconnecting pipe. An additional advantage of this circulating. systemis-thecooling yeii'ect of the exterior pipe, which, if desired, may beexpanded into coils or a radiator A1", thereby radiating any necessaryamount of heat from the oil. Certain other advantages may be gained bycarrying a com aratively high pressure in the operat- .ing c amber. Thismerely requires additional spring pressure on the relief valve B. It isalso advisable to design the relief valve in this case as a plungerVhaving Aports of graduated area.l By adjusting the spring the seats isreturned to The leakage from each higher zone' ers a small quantity ofoil from reserof pump. 'The advantages of this Pressure l systemcomprise better lubrication due to initial pressure on edges of oilfilms; reduction in necessary'size of leakage return ducts wherebyleakage past main piston and valve ressure chamber; suppression oftendency 1n oil to volatilize under high temperature, thereby preventinformation of gasbubbles. The ports G4, 5 in the ends of cylindersprefera' ly have equal or greater area than the cross section ofcyliners themselves. This provides large port area, thereby permittinggreat speed and.`

great efliciency. In order to compensate for .the enlarged ports whichprevent pistons from holding cylinder ba'rrel against valve seat, weintroduce shaft and closely lungers integral with tting in the pressurechambers, which are formed in the self-alining shaft bearings. Thedriving pressure-is automatically maintained in these pressure chambersthrough ducts in the shafts and the check -valve therein. The shafts aremountedin selffalining end bearings which` permit a close fit betweenshaft and bearing to prevent excessive oil leakage from the pressurechambers, and at the same time prevent crampin in bearings due to slightshaft deflections.

4 lie drivers lK1 are keyed to the shaftsl behind the end thrustshoulders and the balance pressure from the chambers Es is communicatedto the barrels Gr-G1 through pairs of compensating washers L1 L3. Thisgives perfect valve face bearing independent of4 shaft deflections. Thebarrels are compelled to rotate with the driver by the drivmg pins L4which transmit only the torque of valve face friction: The compounduniversal joint .consists in a driver and a driven ring, eachl carryinga pair of pins on the transverse axes respectively.- On these two pairsof pins are res ectvely mounted two connecting rings. hese connectingrings are pin connected together on a transverse axis which intersects-the axis of the shaft tol .which thedriver is connected and 1s preferj.ably perpendicular to the .planes of the axes of the driving and drivenrings when they i occupy neutral positions. The plane vin whichthistransverse axis revolves bisects the angIle between the shaft andswashplate, axes.

f here is a slight axial motion as the joint revolves which in thepresent 'invention is permitted by a small sliding movement of a slidingblock at one trunnion atv the lower side of the ring thus preventingbinding or distortion. In order to take up all wear in the drivingparts, and to prevent backlash to as great an extent as possible, it isnecessary to provide means Afor holding the ball ends ofthe connectinrods firmly back in the pistons or in the rivin blocks on the swaslrplates. The blocks an the `swash plate all rotate, but in the-same planeare held by a `single annular plate I.of springbrass or` spring steel,having seven'equally 'pitched holes which are slipped over projectingflanges on the follower rings which hold the ball ends of the connectingrods close into' the sockets.. This plate is held down by seven screwswhich are tapped into the socket ring. These screws pass through thespring plate at points between the connecting rods where the plate isunsup orted and the screws spring the plate Isu ciently to cause it toautomatically follow up any wear 'in 'the ballvends, or in the sockets.Th'e arings, a spring ring I3 is secured to the bearing quill or sleeveJ. The end of this bearing quill is faced off slightly shorter than lthe corresponding face on the socket ring, thereby giving the springring a deflection which always holds the socket ring tightly backagainst the ball thrust bearings. These three devices, which together weterm a spring harness, absolutely prevent any backlash in the movementof the pistons. With this arrangement there xis no excess pressure inthe exhaust port bto keep the pistons forced outward, and the springharness supplies this need. This .is a distinguishing point between thepresent system of returning leakage by casing pressure and the system ofreturning leakage by a pump, which has, been embodied in various othermachines.

f Referring again to Fig. c, a 'will be noted Vthat the ports orlterminations of the dis-l charge passages Gr4 leading from the cylindersto the valve plateform segments of a ring bounded by two concentriccircles g, g",

each segment being separated from its neigh- -bor on either side-.by athin partition wall bounded by adjacent radial lines, g2. Each port thushas two straight and two curved sides, the straight sides radiating fromthe too rapid leakage along the sealing surfaces.

center of the valve plate, and the curved sides formed by concentricvcircles drawn about thecenter'of the valve plate. Each port resembles inshape a truncated pie segment.l The opposed surfaces between the outerrim of the valve face and the concentric circle forming the outer sideofthe ports,

constitute an oil seal. The distance betweenv the two surfaces niust'notbe any` greater than is absolutely necessary to prevent the The circlesbounding ,the outside and the inside of the valve plate port are ofequal diameter with those bounding the cylinder ports and are drawnabout the saine center. There is anappreciable pressure in the film ofoil forced out between these surfaces and this pressure tends to wedgethe cylinder barrel away from the plate so that the smaller the surfacethe smaller the wedging. effect. The substantially radial lines boundingthe ends of the ports are about the same distance apart as theconcentric lines above mentioned, so that the oil seal at the ends ofthe ports is substantially the same as at the side. When once thenecessary width of surface to provide an adequate oil seal has beendetermined, and when once the area of the ports and the cylinderpassages have been selected, the remainder of the Valve seat mustbeina-de to conform in such wise that for any given mean radius minimumpossible unbalanced wedging area. l

It will be understood that the unbalanced wedging or thrust area forminga part of the oil seal supports a pressure which must be overcome bysome suitable externa-l or internal means, as preferably the balancingplunger described at another place.

We claim: Y l

1. A hydraulic transmission comprising a motor and a pump, a pressurechamber contained within and connecting them, a closed housingsurrounding them, and means for keeping said closed housing completelyfull of'oil under pressure.

'2. A hydraulic transmission comprising a motor and a pump, a pressurechamber contained'withinvand connecting them, a closedhousingsurrounding them, and means for keeping said closed housingcompletely full of oil under pressure, a connection between saidpressure chamber and said housing, and means responsive to the operationof motor and pump for controlling said connection.

3. A hydraulic transmission comprising a motor and a pump, a circulatingsystem connecting them having a pressure and a suction side, a closedhousing surrounding them, and means for keeping the closed housingconstantly full of oil under pressure, separate connections between thepressure and suction sides of the circulating system and the housing,and means for controlling them.

4. A hydraulic transmission comprising a motor and a pump, a pressurechamber contained within and connecting them, a closed housingsurrounding them, and means for keeping said closed housing completelyfull of oilfunder pressure, a connection between said pressure chamberand said housing, and means responsive to the operation of motor andpump for controlling saidv connection,

.said means comprising a series of passages, a

,pressure relief valve controlling one of them anda check valvecontrolling another.

5. A hydraulic transmission comprising a motor and a pump, acirculating' system con- `nectin them having-a pressure and a suction sie, a closed housing surrounding them,

and means for keeping the closed housing constantly full of oil underpressure, separate connections between the pressure and suction sides of,the circulating system and 'the housing, .and means for controllingthem,

said means comprising a series of passages,

- a pressurel relief .valve controlling one of them, and a check valvecontrolling another. 6. A hydraulic transmission comprising a motor anda pump, a circulating system connecting them having a pressure and asuction side, a closed housing surrounding them, and means for keepinthe closed housing constantly fullof oi under pressure, separateconnections between the pressure and suction sides of the circulatingsystem and the `housing, and means for controllin them, said meanscomprising passages lea in from the pressure and suction sides, are iefvalve controlling the passage from the pressure side, and a check valvecontrolling the passage from thesuction side.

A hydraulic transmission comprising a motor and pump, a pressure chambercontained within and connecting them, a closed housing surrounding them,and means for keeping said housing constantly full of oil underpressure, and for circulating said oil through said housing independentof conditions 1n the pressure chamber.

8. A hydraulic transmission comprising a motorl and pump,v a pressurechamber contained'within and connecting them, a closed housingsurrounding them, and means for keeping said housing constantly full ofoil i t under ressure, and for circulating said oil i throug saidhousing independent of conditions in. the pressure chamber, said meanscomprising a reservoir and means for pumping oil from the reservoir intosaid housing. 9. A hydraulic transmission comprising a motor and pump, apressure chamber contained within and-connecting them, a closed housingsurrounding them, and means for keeping said housing constantly full ofoil under ressure, and for circulating said oil `and throug said housingindependent ofconditions in the pressure chamber, said means .comprisinga reservoir-and means for pumping oil from thelreservoir into saidhousing, Y ressure relief means discharging 'from said 'ousing tosaidreservoir.y

10..In a hydraulic transmission a fixed valve plate, a cylinder barrel4mounted forl rotation having its discharge end closed by Vsaid late,cylinders contained within said 4barre discharge ports leadingfromsaidlcylinders `to the plate larger in cross sectional area 'than thecylinders, and means removed from the barrel for holding itagainst thelate. v

11. In a iiydraulic transmission a valve plate, a cylinder barrelmounted for rotation with respect to said late, discharge ports leadingfrom the cylin ers therein and controlled by the valve plate saidcylinder ports being larger .in cross sectionall area than therespective cylinders, means for maintaining a hydraulic pressure withinsuch cylinders and plate, and means responsive to such pressure forholding the cylinders firmly against the plate.

12. In a hydraulic transmission a' valve plate, a cylinder barrelmounted for rotation with respect to said plate, discharge ports 'leadinfrom the cylinders therein and controlle by the valve'plate saidcylinder ports being larger in cross sectional area than the respectivecylinders, means for maintaining' a hydraulic pressure within suchcylinders and plate, and means responsive to such pressure forholding-the cylinders against the plate, said means comprising aplunger, a connection between the plunger and the barrel., a c` linderin-Which said plunger operates, an ,a connection from the pressuresystem to said cylinder.

13. A hydraulic transmission comprising a motor and pump, a pressurechamber contained within and connecting them, a closed housingsurrounding them, and means for keepingl said housing constantly full ofoi-l under ressure, and for circulating said oil throng said housingindependent of condi' tions in the pressure chamber, said meanscomprising a reservoir and means for pumping oil from the4reservoir'into said housing, l

and pressure relief meansdischarging from said housing to saidreservoir, said pressure relief being provided with means responsivetowariations in the pressure 'of the oil in the housing for contrllingthe amount of oil discharged therethrough.

14. In a hydraulic transmission a fixed valve plate, a cylinder barrelmounted for rotation having its discharge end closed by Ameans forholding the barrel against the plate.

and controlled thereby, a shaft concentric with the barrel and havingdriving connection therewith, pistons and means for reciprocating themlwithin the cylinder barrel as the shaft and barrel are rotated, andhydraulic means removed from the barrel for yieldingly holding itagainst the plate, the shaft being perforated and communicatingrespectively with the ports of the valve plate and with thesaidhy-draulic means whereby pressure for operating the latter is takenfrom the pressure port of the valveplate through the shaft.

18. A hydraulic transmission comprising a valve plate having portsserving alter- `nately as intake and exhaust ports, a cylinder barrelmounted for rotation with respect thereto and having its discharge endclosedand controlled thereby, a shaft concentric with the barrel andhaving driving connection therewith, pistons and means for reciprocatingthem Within the cylinder barrel as the shaft and barrel are rotated,hydraulic means removed from the barrel for yieldingly holding itagainst the plate, the shaft being perforated and communicatingrespectively With theponts of the valve plate and with the saidhydraulic means whereby pressure for operating the latter, is taken fromthe pressure port of the valve plate through the shaft, and valve meansfor selectively closingithe connection with the exhaust port of the.valve plate and opening that with the pressure port.

` 19. A hydraulic machine comprising a valve plate having annularlyarranged intake and exhaust ports, a cylinder barrel mounted forrotation with respect thereto having axially arranged cylinders ofgreater diameter than the radial width of the ports leading from saidcylinders to said ports in the valve plate, said cylinder ports wherethey discharge 'into the valve plate ports being of substantially thesame radial width as such ports and being bounded at their lends byradial lines and at their sides by concentric circles and narrowdividing'walls between said cylinder ports.

' 20. A hydraulic machine comprising a take and `exhaust valve platehaving annularly arranged intake and exhaust ports, a cylinder barrelmounted for rotation with respect thereto having axially arrangedcylinders of-greaier diameter than the radial width of the valve ,plateports, cylinder ports, leading from the cylinders to the valve plate,such ports where they discharge into valve plate ports being ofsubstantially the same radial width as sa i such ports and being boundedat their ends by radial lines and at their sides by concentric circles.Y i

21, A hydraulic machine comprising a valve plate havingannularlyarranged in-` take and exhaust ports, a cylinder barrel mcantedfor rotation with respect thereto having axially arranged cylinders andports leading from said cylinders to said valve plate ports,.saidcylinder portswhere they discharge into the valve plate'ports being ofsubstantially the same radial width as such iponts and being bounded attheir ends by radial linesand at their sides by concentric circlesand-narrowdividing' walls between said ports.

22. A hydraulic machine comprising aV valve `plate having annularlyarranged intake and exhaust ports, a cylinderV barrel mounted forrotation with respect thereto having axially arranged cylinders andportsleading from said cylinders to the valve plate ports, said cylinderports where they,

discharge into the valve plate ports being of substantially the same.radial Width as such ports and being bounded at their ends by radiallines and at their sides by concentric 23. A hydraulic vmachinecomprising a.- valve plate having annularly arranged inorts, a cylinderbarrel mounted for rotatlon with respect thereto having axiallyarranged'cylinders of greater diameter than the radial width of theports and ports leading from saidcylinders to the .valve plate ports,said cylinder ports where A they discharge into the' valve plate portsbe-A ing of substantially the same radial width as such ports and beingrounded at their ends by radial lines and at their sides by concentriccircles and narrow dividing walls -between said ports, the crosssectional -ar'ea ofeach cylinder port atthe point where it islntersected by the plane of the valve plate being larger than ythe''cross sectional area of its respective cylinder.

24. A hydraulic machine comprising a valve plate having annularlyarranged-.in-

nuiV

take and exhaust ports, Va cylinder barrel mounted. for rotation withrespect thereto having axially arrangedcylinders of greaterdiameter thanthe radial width of the ports' and ports leading from said vcylinders tothe valve plate ports, said cylinder Vports where they discharge intothevalve plate ports being of substantially theI same radial width as suchports and being bounded at'their ends by radial lines and at their sidesby concentric circles, the cross sectional area of each cylinder port atthe point where it 1s intersected by the plane of the valve plate beinglarger than the cross sectional area of its respective cylinder.

25. A hydraulic machine comprising a valve plate having annularlyarranged iny "take and exhaust ports, a cylinder barrel mounted forrotation with respect thereto having axially arran ed cylinders andports leading from said cylinders to the valve plate ports, said'cylinder ports where they discharge into the valve plate ports being ofsubstantially the same radial Width as such ports andbein bounded fattheir ends b y radial lllnes an at their sides by concentric circles andnarrow dividing walls between said cylinder ports, the cross sectionalarea of each'cylinder port at the point where itl is intersected by theplane of the valve plate being larger than the cross sectional area ofits respective cylinder.

26. A yhydraulic machine comprising a valve plate having annularlyarranged intake and exhaust ports, a cylinder barrel mounted forrotation with respect thereto having axially arranged cyllnders andportsIwhere they` discharge into the valve plate ports of substantially thesame radial width as' the valve plate ports and being bounded at their`ends by radial lines and kat their 'sides lby concentric circles, thecross sectional area of each cylinder port at the point Where it isintersected by the plane of the valve plate being larger than the crosssectional area of its respective cylinder.

27. In a hydraulic, transmission having .pump cylinders, pistons thereinand means for operating them, motor cylinders, pistons therein and amember driven thereby, an/oil'- tight housing containing thecylindersand moving parts, 'a reservoir 1n communication with said housing andmeans responsive to the operating'ineans ofthe pump cylinders forforcing fluid from said reservoir into said housing.

28. yIn a hydraulic transmissionl having pump cylinders, pistons thereinand means for operating them, motor cylinders, pistons therein and amember driven thereby, an oiltight housing containing the cylinders andmoving parts, a reservoir in communication with said housin andmeansresponsive to the operation cfg the pump cylinders for forcing fluidfrein said' reservoir into said housing and a/"vpressure reliefdischarge valve controlling the, discharge\of fluid from said housing'vback to said. reservoir.

29. A hydraulic transmission lcomprising aclosedA chamber, powertransmitting means contained therein, a housing comprising a series ofseparate assembly casing parts and means for holding them together,packing surfaces between them, said housing containing the chamber, areservoir also within said housing, bleeder passages disposed withinsaid packin surfaces. between the pressure side and t e holding 'meansand connections, between said. bleeder passages andthe reservoir. i

30. A Vhydraulic transmission comprising a closed chamber, powertransmitting means contained therein, a housing comprising a series ofseparate assembly casing parts and means for holding them together,packing` 4surfaces'between them, said housing containing the chamber, areservoir also within said housing, bleeder passages disposed withinsaid. packing surfaces between the pressure side and the holding 4meansand connections between said bleeder passages and the reservoir andmeans for forcing oil from said reservoir into said closed chamber.

31'. A hydraulic transmission comprising a closed chamber, powertransmitting means contained therein', a housin comprising a Vseries ofseparated assembly casing parts and means for holding them together,packing .surfaces between them, said housing ,containing the chamber,4al reservoir also within said housing, bleeder passa es disposed withinsaidf packing surfaces etween the pressure sideA and the holdin meansand connections vbetween said blee er passages and the reservoir andmeans for forcing oil from said reservoir into said closed chamber andmeansfor controlling the discharge of 33. In a hydraulic-machine a valveplate, I'

a sleeve pro]ecting therefrom, a-shaft rota tably mounted therein, acylinder barrel Arotatably mounted thereon, a housing for. the shaft,sleeve and barrel, a thrust bearing interposed between saidshaftandvsaid housing and a thrust connection between' said shaft and saidcylinder. barrel, said thrust connection and 'thrust bearing each havingvspherical bearing surfaces to permit relative displacementof the partswithout binding. v

34. Inahydraulic machine an apertured valve plate, a sleeveprojectingoutwardly therefrom, ahollow shaft rotatably mountdit@ ed therein, acylinder barrel rotatably mounted on the sleeve, a connection betweenthe apertures inthe valve plate and the interior of the hollow shaft, athrust plunger mounted on said shaft, a cylinder in ywhich it ismounted, a connection between the cylinder and the interior of the shaftand a thrust connection between the shaft and the cylinder barrel.

In a hydraulic machie av packing joint between. opposed memberscomprising smooth contacting surfaces means for holding said surfacestogether the joint between said members'being exposed on one side to ahigh and on the other side to a low pressure a bleeding duct locatedbetween such surfaces and thus between the areas of high and lowpressure and a bleeder pipe communicating with such duct a storagereservoir in which such pipe discharges.

36. A housing, a shaft therein, a sleeve in rotatable engagement withthe shaft, a cylinder therein, a self-alining bearingbetween the sleefeand the housing, a plunger mounted on the shaft in said cylinder andmeans for exerting a pressure within said cylinder against said plunger.fr 37. In a hydraulic transmission a valve plate having exhaust andintake ports, a hub centrally supported by said plate, hollow shaftscontained rotatably within said hub, a plug withinfsaid hub between theends of said shafts, a passage connecting said plug and each of saidports, tubular members extending from said plug and projecting into theends of each of said shafts, said shafts being hollow, plungers on saidshafts, thrust cylinders surrounding said shafts in which said plungersare located and al communication between the interior of said shafts andY the interior of said cylinders.

38. A hydraulic transmission comprising a motor and pump, a'pressure'chamber contained within and connecting them, av closed housingsurrounding them, and means for keeping said housingconstantly full of-oil under pressure, and for circulating said oilthrough said housing,said means compris-l ing a reservoir and means lfor pumping oill fromthe reservoir inte. said' housing.

40. vrA; hydraulic transmission comprising a motorand pump, a pressurelchamber contained within andconnecting them,-a closed housingsurrounding them, and means for keeping said shousing' constantly full of oil under pressure, and. for' circulating said oil through sai-dhousing, said means comprising a reservoir and means for pumping oilfrom the reservoir into said housing, and

pressure relief means discharging from said under pressure, and forcirculating said oil through said housing, said means comprising areservoir and means for pumping oil from the reservoir into saidhousing, and pressure relief means discharging from said housing to saidreservoir, said pressure relief being provided with means responsive tovariations in the pressure of the oil. in the housing for controlling-the amount of oil discharged therethrough.

42. In a hydraulic transmission a fixed ported valve plate, acylinderbarrel mounted for rotation thereon containing a plurality ofcylinders and discharge passages leading therefrom, said passagesextending to and controlled by the valve plate, pistons and means forreciprocating them within said cylinders toward and from the valveplate, the .relative areas of the cylinders, the discharge passages atthe valve plate and the bearing surfaces between the barrel and theplate being such that the-forceexerted by the pistonsis insuiiicient tohold the barrelV `Iirn'ily against the plate and separate pres 'valveplate, the relative areas of lthe cylinders, the discharge passages atthe valve plate and the bearing surfaces between the barrel and theplate being such that the forceexerted by the pistons is insuiicient tohold the barrel. firmly against .the plate, means separate from thecylinder barrel for holding it against the valve plate.

44. In a hydraulicv transmission a fixed ported valve plate, a cylinderbarrel mounted for rotation thereon containing a plurality of cylindersand discharge passages leading therefrom, saidpassagesextendlng to andcontrolled bythe valve plate, pistons and means for reciprocating themwithin said cylinders toward andifrom the val-ve plate,

plate, a cylinder barrel.

the relative areas of the cylinders, the discharge passages at the valveplate and the -bearing; surfaces between the barrel and the i' platebeing such that the force exerted by the pistons is' insuilicient tohold the barrel firmly against the plate, `hydraulic -means separate-f-rom the cylinder barrel for holding it against the valve plate.

45. In a hydraulic transmission a' fixed ported valve plate, -a cylinderbarrel mounted .for rotation thereon containing a plurality of cylindersand discharge passages leading therefrom, said passages extending to andcontrolled by the valve plate, pistons and the 'means Afor reciprocatingthem within said cylinders toward and from the valve plate,

the lre'lative areas of the cylinders, the discharge lpassages at thevalve plate andthe bearing surfaces between the barrel and the platebeing such1that the force exerted by stons is insuicient to hold thebarrel firm y against the plate, hydraulic means responsive to theconditions prevailing within' the cylinders and associate parts forholdin the cylinder barrel firmly against the va ve late.

46. n a hydraulic transmission la fixed ported valve plate, a cylinderbarrel mounted4 for rotation thereon containing a plurality of cylindersand discharge passages leadin therefrom, said passages extending to ancontrolled bythe valve plate, pistons and meanslforv reciprocatingthemwithin said cylinders toward and from the valve plate,

the relative areas of the cylinders, the dischargepassages at the valveplate and the bearing surfaces between the barrel and the plate. beingsuch that the force exerted by the pistons is insuicient to hold thebarrel firm y against the plate,'hydraulic means rel sponsive to theconditions prevailing within a 'cylinder in whichv it is mounte draulicconnection between theinterior` ofthe cylinders and associate parts forholdin thecylinder barrel firmly against the va ve plate, said meanscomprising a (plunger,

-- said cylinder and the interior of the cylinder barrel. f

.47. In a hydraulic. transmission a hydraulic system comprisin aportedvalve plate, a cylinder barrel, a s aft about which the barrel ismounted, and in response to which it` turns and operating members Vmounted' for movement within said cylinder barrel, means surroundingsaid shaft .removed from thev barrel but communicating therewith, forholding the'barrel against the .valve plate, said means comprisingaplunger, a'cylinde'r in which it 'rec1procates,. a communicationbetween such means 'and the system com rising a central' channel throughthe "Said s aa through. which hydraulic pressure is transmitted from thelsystem to the fcylinder.- 4 -1 o 48.4 In a hydraulic ltransmlssion a.fixed l e. valve plate with, or'ts formed therein and a i valve face, a"cy inder vbarrel mounted for -said discharge passages, orts and valveface being so larve that iydraulic pressure within the cyllnders willnot hold the barrel vagainst the valve face, and means removed from thebarrel for holding barrel against the valve face.

49. A hydraulic transmission comprising a valve plate having an annularvalve face with ports therein', a cylinder barrel havingv acorresponding annular valve face, axially arranged cylinders, with meansfor forcing fluid under hydraulic pressure from the cylinders and valve'ports, the valve faces being of such areaA that the hydraulic pressurewithin the cylinders is not suflicient to maintain them in contact,auxiliary means for maintaining valve faces in contact and cylinderports from the respective cylinders to the valve face bounded at theirends b concentric circles and radial lines, where y the maximum portarea is obtained with the minimum valve seat area, equal widths of oilseal surfaces beingmaintained all around each cylinder port.

50. A hydraulic transmission comprising a valve plate having an annularvalve face with ports therein, a cylinder barrel having a correspondingannular valve face, axially arranged cylinders, with means yfor forcingfluid under'hydraulic pressure from the cyl-1 inders and valve ports,the valve faces being of such area that the hydraulic pressure withinthe cylinders is not sufficient to mai-ntain them in contact andcylinder ports from the respective cylinders to the valve face beingmaintained all around each cylinderl port, the width of the oil sealsurfaces being suliicient only to prevent appreciable outflow of oil.

51. A hydraulic transmission having a rotar cylinder barrel, a driversecured thereto an swash plate, a universal driving joint for the swashplate comprising 'two rings articulated respectively to the barrel controlling driver and swash plate and articulated to each other on an axistransverse to the axes of articulation between the rings and the barreland swash plate.

52. vA hydraulic transmission having a swash plate and cylinderbarrelfand means comprising a shaft, a driver "secured to the shaft anddirectly driving the barrel and a universal joint between thexiriver andswashl .plate for driving one from the other at a constant angularvelocity.

53. A hydraulic transmission having a l holding the bearing end of saidconnecting rod to prevent backlash. v

54. Apiston, a cylinder in which it reciprocates, a driving member, aconnecting rod interposed between the driving member-and the cylinder, aspherical bearing at one end of the connecting rod and means for holdingsaid spherical `nearing yieldingly in snug operative position.

55. A driving member comprising a rotary swash plate, a series-ofbearing blocks therein, a series of connecting rods mounted one in eachof said bearing blocks and a spring harness mounted in the drivingmember for yieldingly taking up the backlash between the bearing blocksand the connecting rod ends.

56. A hydraulic transmission having an oil tight housing, joints in thewall'of said housing, bleeder ducts within said joints, a reservoiroutside ofy said housing, pipes leading from said bleeder ducts to saidreservoir, means for pumping a fluid from said reservoir into saidhousing and maintaining a predetermined pressure within said housing.

57. A hydraulic tranmission having an oil tight housing, joints in thewall of said housing, bleeder ducts-within said joints, a reservoiroutside of said housing, pipes leading from said bleeder ducts tol saidreservoir, means for pumping ai Huid from said reservoir into saidhousing and maintaining a predetermined pressure within said housing andmeans for cooling oil during its passage through said pipes.

58. A hydraulic tranmission mechanism, having a power pump mounted in aclosed operating chamber, said pump comprising a high pressure port, ,alow pressure port and ,a passage from operating chamber into said lowpressure port whereby leakage from the high pressure port and cylinderscommunieating therewith is returned into the low pressure port and meansfor maintaining pressure in the operating chamber.v

l59. A hydraulic transmission mechanism, having a power pump mounted ina closed 2 operating-chamber, said pump comprising a high pressure port,a low pressure port and a 'passage from operating chamber into said lowpressure port whereby leakage from the high, pressure port andvcylinders communicating therewith is forced back into the low pressureport and means for maintaining pressure in the operating chamber. l

60.\ A hydraulic transmission, having a power pump mounted in a closedoperating chamber, said pump comprising a high pressure port and a groupof cylinders communichamber, Asaid pump Comprising a high pres- I sureport and a group of cylinders communieating therewith, a low pressureport and a group of cylinders communicating therewith, and a passagefrom operating chamber into said-low pressure port through which leakagefrom the high pressure port and cylinders is returned into the ylowpressure port and means for maintaining pressure in the operatinglchamber.

62. A hydraulic transmission mechanism,

having a power pump mounted in a closed operating chamber, said pumpcomprising a high pressure 'port and a plunger, driving mechanism and aconnecting rod, a low pressure port, a passage from operating chamber tolow pressure port and spring harness to prevent back-lash in the plungermovement,

. whereby the excess o .fgpressure inthe operating chamber abovepressure in low pressure port necessary to force the leakage into thelow pressure port. may be maintained without causing loss of plungermovement.

63. In4 a hydraulic transmission mechanism, a casing dividing thecontained liquid into three zones of varying pressure, a power pumpoperating in the high pressure and intermediate pressure zones, andanother pump operating between the intermediate pressure and lowerpressure zone, said pump adapted to maintain the pressure in theintermediate pressure zone. l

64.- A hydraulic transmission mechanism, comprising a casing, a powerpump and .anauxiliary pump, so arranged that the contained liquid isseparated into three pressure zones', the total combined volume of the:

. means for maintaining the pressure in the l intermediate zone.

65. A hydraulic transmission mechanism comprising a casing, a power pumpand an auxiliary pump, so arranged that thecontained liquid is separated-into three pres` sure zones, the'total combined volumeof the highestand intermediate pressure zones being vconstant and limited by a closedoperating chamber, and an auxiliary pump adapted to returnthe leakagefrom the lowest pressure zone to the intermediate pressure zone, andadapted thereby to maintain the pressure in thel intermediate pressurezone.

66. In a hydraulic transmission, a casing dividing Vthe contained liquidinto ,three zones of varying pressures,a power pump operating in thehlgh pressure and intermediate yessure zone, and another pump oper.-ating tween the intermediate pressure and low pressure zone,

intermediate and low ressure zone, vsaid wall being pierced only yleakage passagesy and by the auxiliary pump passage.

Signed at .Mi1waukee, county of Miland a wall between saidv waukee andState of-Wisconsin, this 7 day '115 of February, 1916.

WALTER FERRIS. 'In the presence of Witnesses:

GEO. H. RONDEAU, KATHRYN OCONNELL. .Signed at South Milwaukee, county ofMilwaukee and State of Wisconsin, this 7 day of February, 1916.

WILLIAM-E. MAGIE. In the presence of witnesses:

GEO. H. RoNDnAU, KATHRYN OCoNNnLL.

